Surge absorber

Abstract

A surge absorber has a first terminal electrode, a second terminal electrode, a third terminal electrode, an inductor portion, a surge absorbing portion, and a capacitor portion. The inductor portion has a first internal conductor and a second internal conductor mutually coupled in a polarity-reversed relation. One end of the first internal conductor is connected to the first terminal electrode. One end of the second internal conductor is connected to the second terminal electrode. The other end of the first internal conductor is connected to the other end of the second internal conductor. The surge absorbing portion has a first internal electrode connected to a connection point between the first internal conductor and the second internal conductor, and a second internal electrode connected to the third terminal electrode. The capacitor portion has a capacitance component connected between the first terminal electrode and the second terminal electrode.

1. A surge absorber comprising:
 a first terminal electrode; 
 a second terminal electrode; 
 a third terminal electrode; 
 an inductor portion having a first internal conductor and a second internal conductor mutually coupled in a polarity-reversed relation, wherein one end of the first internal conductor is connected to the first terminal electrode, one end of the second internal conductor is connected to the second terminal electrode, and an other end of the first internal conductor is connected to an other end of the second internal conductor, the coupling between the first and second internal conductors being positive and not negative; 
 a surge absorbing portion having a first internal electrode connected to a connection point between the first internal conductor and the second internal conductor, and a second internal electrode connected to the third terminal electrode; and 
 a capacitor portion having a capacitance component connected between the first terminal electrode and the second terminal electrode, 
 wherein the inductor portion is comprised of a lamination of a first inductor layer on which the first internal conductor is formed, and a second inductor layer on which the second internal conductor is formed, 
 the surge absorbing portion is comprised of a lamination of a first varistor layer on which the first internal electrode is formed, and a second varistor layer on which the second internal electrode is formed, 
 each of the first and second varistor layers contains ZnO as a principal component and contains at least one element selected from the group consisting of rare earths and Bi, and Co as additives, 
 each of the first and second inductor layers contains ZnO as a principal component and contains rare earths as additives, and substantially does not contain Co, and 
 a content of the additives in the first and second inductor layers is not less than 0.02 mol % or more than 2 mol %, based on a total amount of ZnO in the first and second inductor layers. 
 
     
     
       2. The surge absorber according to  claim 1 , wherein the capacitance component of the capacitor portion is formed by the first internal conductor and the second internal conductor. 
     
     
       3. The surge absorber according to  claim 1 , wherein the capacitor portion has a third internal electrode connected to the first terminal electrode, and a fourth internal electrode connected to the second terminal electrode, and
 the capacitance component of the capacitor portion is formed by the third internal electrode and the fourth internal electrode. 
 
     
     
       4. The surge absorber according to  claim 1 , wherein the first internal conductor and the second internal conductor include mutually overlapping regions when viewed from a laminate direction of the first and second inductor layers, and
 the first internal electrode and the second internal electrode include mutually overlapping regions when viewed from a laminate direction of the first and second varistor layers. 
 
     
     
       5. The surge absorber according to  claim 1 , further comprising an element body including the inductor portion, the surge absorbing portion, and the capacitor portion,
 wherein the first terminal electrode, the second terminal electrode, and the third terminal electrode are placed on an external surface of the element body, and 
 the other end of the first internal conductor, the other end of the second internal conductor, and the first internal electrode are connected through an external conductor placed on the external surface of the element body. 
 
     
     
       6. The surge absorber according to  claim 1 , wherein the first terminal electrode is an input terminal electrode,
 the second terminal electrode is an output terminal electrode, and 
 the first internal conductor and the second internal conductor are positively coupled. 
 
     
     
       7. The surge absorber according to  claim 1 , further comprising:
 two or more of each of the first terminal electrode, the second terminal electrode, the third terminal electrode, the first internal conductor, the second internal conductor, the first internal electrode, and the second internal electrode.